ConstructBinaryTreefromInorderandPostorderTraversal

//Given inorder and postorder traversal of a tree, construct the binary tree.
//
//Note:
//You may assume that duplicates do not exist in the tree.
public class ConstructBinaryTreefromInorderandPostorderTraversal {


public static void main(String[] args) {
// TODO Auto-generated method stub


}
public TreeNode buildTree(int[] inorder, int[] postorder) {
if(postorder.length==0)
return null;
int count=inorder.length;
TreeNode root=new TreeNode(postorder[count-1]);
int i;

for(i=0;i<count;i++){
if(inorder[i]==postorder[count-1])
break;
}
TreeNode left=create(postorder,0,i-1,inorder,0,i-1);
TreeNode right=create(postorder,i,count-2,inorder,i+1,count-1);
root.left=left;
root.right=right;
return root;
    }
private TreeNode create(int[] postorder, int s, int e, int[] inorder, int si, int ei) {
// TODO Auto-generated method stub
//没有元素了
if(s>e)
return null;
TreeNode root=new TreeNode(postorder[e]);
int i;
for(i=si;i<=ei;i++){
if(inorder[i]==postorder[e])
break;
}
TreeNode left=create(postorder,s,s+i-1-si,inorder,si,i-1);
TreeNode right=create(postorder,s+i-si,e-1,inorder,i+1,ei);
root.left=left;
root.right=right;
return root;
}


}